TAC 51X Rack PSU Build

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Having decided to venture down the 51X route, I took the plunge and ordered a 51X "Basic" 11 slot rack, floor PSU and two pre's from Sahib at Total Audio Control (TAC).

All arrived promptly by courier in a very well packaged box.

Having read through Chunger's Newbie build threads on this board, I thought that it might be useful to post a couple of pics of the salient parts of the Tac Rack build.

 

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The floor box PSU seemed like the logical place to start.
All of the PSU bits and pieces were packed into the PSU case. All clearly identified in their respective zip-locked bags.

In my experience, the PSU build often pays dividends with a patient approach due to the amount of wiring that needs to be completed in the case.  Tidy layout and routing eliminates errors during the build and also facilitates easier fault finding, should that be required at some stage in the future.

 

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Led's and Fuse holders installed and wired. Covering the solder terminals with the supplied heat-shrink tubing adds mechanical strength but more importantly eliminates accidental shorting.

 

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On to the PCB's
Nothing too complicated here, just follow the instructions with regards to soldering a couple of the regulator pins whilst the boards are on their mountings and in the correct position. This ensures that the regulators fit correctly to their respective mounting holes. Having soldered a couple of pins (one pin each is actually sufficient) on each regulator, the boards can be removed and stuffed with the remaining components.
(If this is your first build, start with the components that are the flattest against the board and work up - resistors, diodes, then caps and trimmers and so on)
I also decided to put a couple of blobs of silicone around the bases of the large caps, just to provide a little extra support.

 

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Completed PCB's installed and ready to be wired.

 

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Wiring the rear panel connectors came next. Again, it is a good idea to cover the terminals, once soldered, with the heat-shrink tubing.

 

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This pic shows the voltage selector switch - double check the wiring instructions, paying particular attention to the colour coding of the wires relative to the switch position. What the switch does, is place the two transformer primary windings in parallel for 110V and series for 220V.

 

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I decided to route all the wires that needed to go to the star ground connector bolt between the 16V and 48V PCB's. These wires were then secured using cable ties and a couple of adhesive cable tie pads - the adhesive pads were not included but are pretty readily available. The pads  not only keep the wires where you want them to stay, they also lift the wires off the case where there is a possibility of abrasion.

 

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Secure all of the ground and earth wires to the common star ground pin at the back of the case.

 

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The last remaining challenge was the nine pin connector. Bear approximately 22mm of the outer insulation and tin the ends. Don't forget to slide the outer housing and cable gland onto the cable before you start soldering!  It is also very much easier to solder the connector terminals under one of those "helping hands" magnifying glasses, in good light.
It is also important, once again, to cover each of the terminals with heat shrink tubing to prevent accidental shorts.

 

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All that remains is to double check all the wiring before installing fuses  and applying power. I like to do this one step at a time. Main power supply fuse first (the one in the IEC connector at the back) - power on the unit and verify transformer voltages at the AC input to each PCB. If all is OK, switch off and allow some time for the caps to discharge (five minutes or so). Install fuses into the 16V holders, power up  and set the 16V pos & neg by adjusting the trimmers - power down & discharge caps. Repeat for 24V and 48V.

Everything worked fine first time around and I am sure that this PSU will be a solid, stable (pun intended) companion to the rack in the studio for many years to come.

Now for the rack!